赤泥使用石灰窑尾气脱碱的模拟实验

Simulation experiments for dealkalization of red mud by limekiln gas

通过对山西某铝厂赤泥的基础特性分析,提出用含CO2为20%左右的石灰窑尾气对赤泥进行脱碱模拟实验。热力学分析表明利用石灰窑尾气脱碱是可行的,而实际影响脱碱的主要为动力学因素。实验以脱碱率为指标,分析液固比、CO2体积分数、CO2摩尔比、搅拌速度和反应温度5个因素对赤泥脱碱率的影响。研究结果表明,合理的脱碱工艺参数为:液固比8mL/g、CO2体积分数20%、CO2摩尔比40、搅拌速度400r/min和反应温度60℃,该工艺条件下的脱碱率为31.10%。实验结果表明,可以利用含CO2为20%左右的石灰窑尾气对赤泥进行脱碱处理,该工艺能脱除赤泥中的可溶性碱,符合"以废治废"的循环经济理念。

Through analyzing the basic characteristic of red mud from an aluminum factory in Shanxi,a dealkalization simulation experiment of red mud with lime kiln tail gas containing CO2 around 20% is proposed.Thermodynamic analysis shows that dealkalization by using lime kiln exhaust is feasible,and the actual main factors affecting dealkalization are the dynamics factors.Experiments take dealkalization rate as an index,the influence of liquid-solid ratio,CO2 volume fraction,CO2 mole ratio,stirring speed and reaction temperature of red mud on dealkalization rate are researched and the results are as follows.The reasonable parameters for dealkalization are liquid-solid ratio 8 mL/g,CO2 volume fraction 20%,CO2 mole ratio 40,stirring speed 400 r/min and reaction temperature 60 ℃,and the dealkalization rate under these process conditions is 31.10%.The study results show that lime kiln tail gas of containing CO2 at around 20% could be used for red mud dealkalization treatment,and this process can remove the soluble alkali in red mud,which conforms to the concept of “using waste treat waste”.